AT WCE 2017

VANCOUVER (FRONTLINE MEDICAL NEWS) – Intravaginal onabotulinumtoxinA (Botox) injections relieved chronic pelvic pain in women with endometriosis in a small National Institutes of Health study, suggesting that it might be time to think about pelvic floor muscle spasms when pain persists despite optimal treatment.

The 11 women in the study reported a baseline median pelvic pain score of 6 out of 10; they all had pelvic floor muscle spasms on gynecologic exam, and nine of the women had spasms in four or more muscles. All of the women had surgically-confirmed endometriosis and pelvic pain that didn’t go away even after their endometriosis was treated with hormones and surgery, a common problem in endometriosis care and a frequent topic of discussion at the World Congress on Endometriosis, where the study was presented.

Spasm trigger points were identified on gynecologic exam. “I used my finger [to press] those muscles to find the trigger points” with the help of patient feedback. Often, they felt like knots under the vaginal skin, said lead investigator Pamela Stratton, MD, an ob.gyn. with the National Institutes of Health in Bethesda, Md.

The women were given diazepam; the trigger points were prepped with lidocaine cream and then injected with 100 units of onabotulinumtoxinA in 4 mL of saline.

A month or so later, spasms were either absent or less widespread, involving just a muscle or two. Nine of the 11 women said their pain was mild or resolved, and the median pain score had fallen to 1 point. Five women had reduced their pain medications, and three of the five who reported at least moderate disability before the shots said they were doing better afterward. Three of the 11 women requested a second injection at the end of follow-up at 6-12 months.

“Pelvic floor spasms are a major” – but underrecognized – “component of chronic pelvic pain” in women with endometriosis, Dr. Stratton said. When pain persists despite surgery and hormones, “you need to look at where the pain is being generated. As gynecologists, we can find the focus of pain if we do a careful exam. We found remarkable relief” when spasms were released with onabotulinumtoxinA.

Dr. Stratton reported on the 11 of 16 women who requested open label onabotulinumtoxinA injections a month or more after participating in a randomized, blinded trial of onabotulinumtoxinA versus saline for chronic pelvic pain. The randomized trial is ongoing, and she expected results to published in 2017.

She used hollowed-out acupuncture needles to deliver the toxin intravaginally, with a protective sheath to avoid inadvertent injections, and electromyography to ensure the shots went into muscle.

It’s been known for some time that muscle spasms cause chronic pelvic pain, and that onabotulinumtoxinA can bring relief. Even so, it hasn’t been studied before in a strictly endometriosis population. Perhaps in some women with endometriosis, muscles tense up to protect painful lesions, as they do in peritonitis, except that pelvic muscles stay tense even after pelvic lesions are addressed.

Gynecologic physical therapy is the usual option for pelvic muscle spasms, but women have to keep going back to the office and the treatment can be intrusive. OnabotulinumtoxinA injections offer the possibility of a simpler, quicker treatment that lasts longer, maybe 6 months or a year, after which it can be repeated.

The median age of the women was 30 years. They had reported pelvic pain for over a decade despite endometriosis treatment. Most went into the study on anovulatory hormones.

Allergen, the maker of Botox, supplied the medication and paid for data monitoring. Dr. Stratton said she has no personal financial relationship with the company, but noted that Allergan is working toward a chronic pelvic pain indication for the medication.

aotto@frontlinemedcom.com

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